In the season one finale of The X-Files, "The Erlenmeyer Flask," a man with green blood collapses and emits a poisonous gas when paramedics attempt to perform a needle compression. Then, when he is killed later in the episode, Mulder passes out from the fumes emitted from his wound. It is revealed that his blood is acidic because he is an alien-human hybrid, and alien blood is toxic to humans. This recurs throughout the series, most notably when the human-shaped alien bounty hunters bleed green acidic blood.

Of course, we have not found alien life in real life, nor do we have any idea whether it's possible that extraterrestrials would have acidic blood. Nevertheless, this aspect of the mythology is based on a real-life incident. On February 19, 1994, Gloria Ramirez went to a hospital in Riverside, California with symptoms of advanced cervical cancer. The hospital staff noticed white particles and an ammonia-like smell when they drew her blood, and everyone in close proximity began to get sick. Three people passed out, 23 became ill, and five had to be hospitalized. One hour later, Ramirez was dead of kidney failure. The ER was evacuated and Hazmat teams decontaminated the room.

"If this were a fictitious incident in an X-Files episode, Mulder and Scully would have arrived soon afterward, Scully would have conducted the autopsy, finding some scientific basis for the white flecks in Gloria's blood," Simon writes. "Mulder would have questioned family members about whether Ms. Ramirez complained of being an alien abductee or whether she recently visited sites of illegal pesticide sprayings. The case would be resolved and the X-File closed. Life, however, rarely imitates fiction. The autopsy of Ms. Ramirez was inconclusive. White particles in her blood could not be explained."

One explanation was proposed, involving a powerful chemical called dimethyl sulfide, which could have been applied to Gloria's body as a home remedy for pain resulting from her cancer. It can crystallize at room temperature, explaining the white flecks, and scientists proposed that it could have converted into dimethyl sulfate from the electric shocks from the defibrillator, which is an extremely poisonous gas that could cause the medical staff to pass out. However, other experts pointed out that it's never been proven that this chemical conversion has ever taken place, or even that it can take place, making this explanation fairly unlikely.

The other popular explanation was mass hysteria, which is even more unlikely. Many of the affected nurses and doctors experienced health problems long after the incident, especially the ones who were closest to Gloria's body.

"Dr. Julie Gorchynski, one of the first affected, had been a champion surfer in glowing health. Muscle spasms and oxygen loss following the incident have led to a rare destructive bone disorder. This real X-File remains open and unsolved."